CALCIUM: BLOOD-BRAIN BARRIER AND CNS PATHOPHYSIOLOGY

临床低钙血症和高钙血症经常伴有紊乱 中枢神经系统的功能，通常归因于异常 脑间质钙活性 与此明显矛盾的是 发表的实验室报告强调离子的独立性， 脑脊液和脑间质液中的活性 从血液循环中分离出来。 本项目旨在 解决这一冲突，它有两个主要目标：A。 确定 脑间质钙活性依赖于血浆的程度 离子钙和总钙，以及血浆和脑pH值B。 以确定 脑组织钙活性改变对脑缺血再灌注损伤的影响 功能 为了实现这些目标，钙的急性和慢性变化 活动水平将被诱导。 呼吸和代谢的影响 对血液和脑组织中钙活性的影响， 还将观察神经元功能。 此外， 改变钙、镁、pH和pO2水平对神经元功能的影响， 评估。 将在循环中测量离子钙活性和pH值。 动脉血和脑间质间隙中的离子选择性 个电极 将用极谱法测量氧张力， 微电极 此外，总Ca、Mg、pH、pO2，在某些情况下， 实验，甲状旁腺素水平，将在动脉样本中测量 血 神经功能，包括EEG、癫痫发作阈值、诱发 电位，兴奋性和抑制性突触功能，神经元膜 将在完整的大脑和脊髓以及大脑中评估特性。 保持在体外的组织切片。

Clinical hypo- and hypercalcemia are frequently accompanied by disturbed function of the central nervous system, usually attributed to abnormal cerebral interstitial calcium activity. In apparent contradiction to this view, published laboratory reports emphasize the independence of ion activities in both cerebrospinal fluid and in cerebral interstitial fluid from that in circulating blood. The project proposed here is designed to resolve this conflict and it has two major goals: A. To determine the degree to which cerebral interstitial calcium activity depends on plasma ionized and total calcium, and on plasma and cerebral pH. B. To determine the effect of altered cerebral tissue calcium activity on cerebral function. To achieve these goals acute and chronic changes of calcium activity levels will be induced. The effects of respiratory and metabolic alkalosis on calcium activity in blood and in cerebral tissue and on neuronal function will also be observed. Further, the interactions of altered calcium, magnesium, pH and pO2 levels on neuronal function will be evaluated. Ionized calcium activity and pH will be measured in circulating arterial blood and in cerebral interstitial space with ionselective electrodes. Oxygen tension will be measured polarographically with a microelectrode. In addition, total Ca, Mg, pH, pO2, and, in some experiments, parathormone levels, will be measured in samples of arterial blood. Neuronal functions, including EEG, seizure threshold, evoked potentials, excitatory and inhibitory synaptic functions, neuronal membrane properties will be assessed in intact brain and spinal cord and in cerebral tissue slices maintained in vitro.